Current studies have shown that the protein concentration of rat parotid saliva is affected when the same stock diet that is fed to the control rats is prepared to increase or decrease the requirement for mastication. With reduced mastication the protein composition is also affected and proline-rich proteins are preferentially reduced. This is in contrast to chronic isoproterenol treatment for which the prolinerich proteins are preferentially increased. Of five basic proline-rich proteins normally present, four are essentially absent with reduced mastication. These are the only four present with chronic isoproterenol treatment. To determine the alterations in the protein composition of parotid saliva with increased mastication, the secretory proteins will be separated into seven groups by ion-exchange chromatography and the percent of protein in each group compared to that of the control. The basic proline-rich proteins will be further separated by gel filtration and ion exchange chromatography into five fractions. The percent of protein in these five fractions will be compared to that observed for the rats fed the control diet and for those fed the same diet but prepared to reduce mastication. A technique will be developed to separate the acidic proline-rich proteins into component groups and these will be characterized as to their mobility in acrydlamide gels, their amino acid composition and their carbohydrate content. The acidic proline-rich proteins in the parotid saliva of rats fed the same diet but prepared to increase or to decrease mastication and in the parotid saliva of rats subjected to chronic isoproterenol treatment will be separated and the percent of protein in the individual fraction component groups will be compared to that of rats fed the control diet. At the conclusion the concentration of the seven groups of proteins in parotid saliva as well as the concentration of individual acidic and basic proline-rich proteins will be determined for each of the diets and for chronic isoproterenol treatment and significant differences identified.